10513 - To oversee the field support and computer support contracts responsible for annual follow-up of study subjects from the PLCO trial and construct analyzable data sets for use by investigators throughout the division. The Division of Cancer Prevention (DCP, formerly DCPC), under extramural contracts to 10 U.S. clinical centers, is evaluating the effectiveness of screening for prostate, lung, colorectal and ovarian cancer (The PLCO Trial). In 1996 the NCI Executive Committee approved the expansion of the PLCO Trial to collect additional materials and to conduct additional studies. About, 74,000 men and 74,000 women, aged 55-74 years, have been randomized on a 50/50 basis into screening or usual care arms. Additional blood is collected from screened subjects and Saliva/Buccal Cells for buccal cells from control subjects. Pathologic tissues are obtained for selected cases that develop cancer or selected related diseases (e.g. colon polyps, benign prostatic hyperplasia). Additional questionnaire-based risk and disease-related information is also collected, with confirmation of disease status from medical records. Genetic, biochemical and questionnaire-based risk information will be related to the development of cancer and other diseases in this population. Volunteers who provide samples for these studies will not routinely receive their individual results from the Additional Investigation. Subjects requesting such information, however, will be provided their test results. In 2009 the NCI Executive Committee approved the Extended Follow-up of subjects beyond the original 13-year follow-up period. Participants will be reconsented for the release of records to a single NCI-Designated Central Data Collection Center (CDCC), which will administer the annual mailings containing the annual study update questionnaire and a brief (1-2 page) risk factor questionnaire. Individuals who do not consent to release their identifiers to the CDCC will be followed up passively through linkage to state cancer registries and the National Death Index. l Death Index.